1. Field of the Invention
The present invention concerns a method for closing boxes of cardboard, corrugated board or analog sheet material with a square or rectangular cross-section, while reducing, when this turns out to be desirable, the height of these boxes to that of their content. It is also about a machine capable of carrying out the various stages of this method.
The technical field of the invention is that of machines for processing, cutting, setting up or closing of packaging or of manufacturing and implementation of methods and cushioning materials for such packaging.
The present invention concerns more particularly the closure and height adjustment of boxes used for the handling of single or multiple-item orders and more generally of boxes used for the packaging, prior to shipping them to customers or other addressees, of diverse items varying in number and unit volume, and thus also in overall volume, from one box to the next.
2. Description of Related Art Including Information Disclosed under 37 CFR 1.97 and 37 CFR 1.98.
It is known that boxes of this type are formed by machines starting with one or several panels of rigid and pliable material, featuring various flaps and fold-downs that are inter-connected using either glue or adhesive tape.
One is familiar with boxes which, after having been formed, consist of five walls, i.e., a square or rectangular base and a belt composed of four side walls inter-connected at right angles forming ridges. Boxes of this type are for example known under the name of “American half-boxes”, “trays” or “bell boxes”. These boxes are usually, after having been filled, closed by a lid. One is also familiar with lids which have four flaps which are folded down and glued on the sides of the box. Also known are lids where the different flaps have previously been shaped by nesting or by gluing; these lids are placed over the top of the box and become one with the box through gluing, stapling or a metal or plastic strip.
One is also familiar with boxes which, after forming, are composed of a base and four side walls like the boxes described above, as well as of four upper flaps. Each of these upper flaps is connected to one of the side walls of the box through a crease line. The boxes of this type are known as “American boxes”. Once filled, these boxes are closed by folding the four upper flaps in a horizontal plane and keeping these flaps in place through gluing, stapling or a metal or plastic strip.
All boxes described above, and, generally speaking, most boxes used for the packaging of objects share the common characteristic of providing a constant useful volume, once they have been set up and closed.
Various products are often employed by users or integrated in the box-forming and closing machines, to immobilize the various, previously packed objects the overall volume of which can vary from one box to the next.
This solution presents numerous disadvantages. In effect:                These products are frequently costly;        except when they are made of the same material as the packaging itself, they must necessarily be separated from the carton material prior to collection and possible recycling of the corresponding waste material; on the other hand, the materials used are in most cases difficult to recycle; this collection and this recycling are complex and very costly operation;        their implementation is difficult and requires either complex automated machinery or many hours of manual labor; the cost of these operations is accordingly high;        the volume shipped, which ideally should be equal to the volume of the manufactured box, is, most often, vastly superior to the actual volume used, which is equal to the volume of the objects placed inside the box; this results in high shipping costs for said boxes.        
One also knows about methods consisting of reducing the box height in order to bring it in line as much as possible with the height of the packed goods.
One is familiar, in particular, with a method (EP-2584802A1) which consists of cropping and discarding the high portion of boxes, situated above the upper level of the stack of objects placed inside said boxes so as to reduce its height to the useful height of the latter. This document describes a method for reducing the height of box made of a pliable material, consisting of a base and at least four side walls, up to the top level of the stack of objects previously placed in said box, without removing a portion of material of said box, but by folding the high sections of said side walls towards the center of said box. According to this method:                the links between said side walls are cut along the upper portion of the vertical ridges of said box, between the top of said vertical walls of the box and the level of the top of said stack of objects previously placed in the box,        all high sections of said side walls are then folded back toward the inside of said box in order to bring them back into an essentially horizontal plane.        
Analog methods are described in documents in FR-2292626, FR-2919520, EP-1832413.
The method described in document EP-2684802 presents disadvantages which are present in the three other afore-mentioned documents. In particular:                cutting the box is a delicate operation which implies the utilization of cutting tools which are dangerous and subject to rapid wear which means that they have to be frequently sharpened or replaced;        automatic removal of the cut upper portion of the box is a difficult operation which is also prone to generate dust and other waste which need to be collected and eliminated;        automatization of this method requires the availability of complex machines.        
Document EP 2684802 also describes a machine for the cushioning and containment of objects inside a box made of pliable material, for example cardboard, consisting of a base of square or rectangular or approximately square or rectangular shape, and of four side walls, this machine featuring tooling for adapting the height of the useful volume of the box to the height of the stack of objects placed inside it and for closing said box, and means for either moving this tooling so as to position it above the box or for moving said box to position it below said tooling.
Similar machines are known from documents FR-2292626, FR-2919520, and EP-1 832413.
Also known are documents EP-1817483 and FR-2818230 which describe a machine and a method which consists of cutting the four vertical edges of a box, from its top to a height corresponding essentially to that of the top of the stack of packed objects and then create a horizontal scoring (or groove) on each of the four side walls of the box at this same height, and finally to fold towards the inside of the box, around these horizontal scores and at an essentially right angle, the upper portion of these four side walls. This method also allows adjusting the height of the box by reducing it to the useful height. Furthermore, when the distance between the top of the stack of objects and the top of the box is equal to or greater than the half width of the box, the upper portion of one of the two side walls parallel to the length of the box must at least come into contact and possibly pass above the high portion of the second side wall parallel to the length of the box during the folding, so that they occupy, once folding is complete, the entire upper surface of the box, possibly by one partially overlapping the other in the middle of said box. It is thus possible to simply close the box by providing a means to maintain said high sections in the folded position, for example through gluing.
This last method presents nevertheless some disadvantages, such as:                cutting the four vertical ridges is a delicate operation which implies the utilization of cutting tools which are dangerous and subject to rapid wear;        these cutting operations generate dust and other waste which pollute the context of the box, as they can fall into it during said cutting operations.        
The problem at hand is therefore to provide a means for reducing the height of a box, featuring a base and at least four side walls, as closely as possible to the objects previously placed into this box and to simultaneously close said box while using for this purpose the material the box is made of, without supplying any additional board material and without the use of any cutting tool whatsoever.